Bresenham算法绘制线段并利用“橡皮筋”功能绘制折线

#include<windows.h> #include<GL/glut.h> #include<GL/gl.h> #include <iostream.h> #include <ctime> #include <cstdlib> #include<math.h> #define pointSize 1 class point4 { public: point4(){startx=0;starty=0;endx=0;endy=0;} int startx; int starty; int endx; int endy; }; point4 array[20]; int line_number; int startX,startY,endX,endY; int mouse_button_state;//0:没有操作 1:第一个点刚按下 2:松开点 int mark; void lineBresPlane(int xStart,int yStart,int xEnd,int yEnd) { int x, y, xx, yy; if( xStart>xEnd ) { x = xEnd; y = yEnd; xx = xStart; yy = yStart; } else { x = xStart; y = yStart; xx = xEnd; yy = yEnd; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); while(x<xx) { x ++; glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); } } void lineBresApeak(int xStart,int yStart,int xEnd,int yEnd) { int x, y, xx, yy; if( yStart>yEnd ) { y = yEnd; x = xEnd; yy = yStart; xx = xStart; } else { y = yStart; x = xStart; yy = yEnd; xx = xEnd; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); while(y<yy) { y ++; glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); } } void lineBresDiagonal(int xStart,int yStart,int xEnd,int yEnd) { int x, y, xx, yy; if( xStart>xEnd ) { x = xEnd; y = yEnd; xx = xStart; yy = yStart; } else { x = xStart; y = yStart; xx = xEnd; yy = yEnd; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); bool flag = false; if(yy>y) flag = true; while(x<xx) { x ++; if(flag) y ++; else y --; glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); } } void lineBresXbig(int xStart,int yStart,int xEnd,int yEnd) { int dx = fabs(xEnd - xStart), dy = fabs(yEnd - yStart); int p = 2*dy - dx; int twoDy = 2*dy, twoDyMinusDx = 2*(dy-dx); int x, y, xx, yy; if( xStart>xEnd ) { x = xEnd; y = yEnd; xx = xStart; yy = yStart; } else { x = xStart; y = yStart; xx = xEnd; yy = yEnd; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); bool flag = false; if(yy>y) flag = true; while(x<xx) { x ++; if(p<0) p += twoDy; else { if(flag) y ++; else y --; p += twoDyMinusDx; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); } } void lineBresYbig(int xStart,int yStart,int xEnd,int yEnd) { int dx = fabs(xEnd - xStart), dy = fabs(yEnd - yStart); int p = 2*dx - dy; int twoDx = 2*dx, twoDxMinusDy = 2*(dx-dy); int x, y, xx, yy; if( yStart>yEnd ) { y = yEnd; x = xEnd; yy = yStart; xx = xStart; } else { y = yStart; x = xStart; yy = yEnd; xx = xEnd; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); bool flag = false; if(xx>x) flag = true; while(y<yy) { y ++; if(p<0) p += twoDx; else { if(flag) x ++; else x --; p += twoDxMinusDy; } glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); } } void myinit() { glClearColor(1.0,1.0,1.0,0.0); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glColor3f(0.0, 1.0, 0.0); glPointSize(pointSize); glOrtho(0.0,799.0,0.0,699.0,-1.,1.); glMatrixMode(GL_MODELVIEW); glEnable(GL_COLOR_LOGIC_OP); line_number=0; } void flood_fill(int x,int y){ int iPixel = 0; glReadBuffer(GL_FRONT); glReadPixels(x, y, 1, 1,GL_RED, GL_INT, &iPixel);//读取一点的红色通 if(iPixel!=0) { glBegin(GL_POINTS); glVertex2i(x, y); glEnd(); flood_fill(x-1,y); flood_fill(x+1,y); flood_fill(x,y-1); flood_fill(x,y+1); } } void drawline(int startx,int starty,int endx,int endy) { int dx = fabs(endx - startx), dy = fabs(endy - starty); if(dx==0) lineBresApeak(startx,starty,endx,endy); else if(dy==0) lineBresPlane(startx,starty,endx,endy); else if(dx==dy) lineBresDiagonal(startx,starty,endx,endy); else if(dx>dy) lineBresXbig(startx,starty,endx,endy); else lineBresYbig(startx,starty,endx,endy); glFlush(); } void motion(int x, int y) { if(mouse_button_state==1){ glLogicOp(GL_XOR); drawline(startX,startY,endX,endY); endX=x; endY=700-y; glLogicOp(GL_XOR); drawline(startX,startY,endX,endY); } } void mouse(int button,int state,int x,int y) { if((mark==0) && (button == GLUT_LEFT_BUTTON)) { if((mouse_button_state ==0)&&(state == GLUT_DOWN)) //第一次按下 { mouse_button_state = 1; startX = x; startY = 700-y; } else if((mouse_button_state ==1)) //长按后松掉 { mouse_button_state = 0; glLogicOp(GL_XOR); drawline(startX,startY,endX,endY); endX=x; endY=700-y; array[line_number].startx=startX; array[line_number].starty=startY; array[line_number].endx=endX; array[line_number].endy=endY; line_number++; glLogicOp(GL_COPY); drawline(startX,startY,endX,endY); } } if((mark==1) && (button == GLUT_LEFT_BUTTON)){ int x1=x; int y1=700-y; flood_fill(x1,y1); } } void display(void) { glLogicOp(GL_COPY); glClear(GL_COLOR_BUFFER_BIT); if(line_number!=0){ for(int i=0;i<line_number;i++) drawline(array[i].startx,array[i].starty,array[i].endx,array[i].endy); } } void menu(int id) { if(id == 1 ) mark=0; if(id == 2) mark=1; } void reshape(int w, int h) { glutPostRedisplay(); glViewport(0, 0, w, h); } void keyboard(unsigned char key, int x, int y)//Esc { switch (key) { case 27: exit(0); break; } } void main(int argc,char **argv) { srand(time(0)); glutInit(&argc,argv); glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB); glutInitWindowSize(800,700); glutInitWindowPosition(0,0); glutCreateWindow("bresenham"); myinit(); glutReshapeFunc (reshape); glutDisplayFunc(display); glutKeyboardFunc (keyboard); glutMouseFunc (mouse); glutMotionFunc (motion); glutCreateMenu(menu); glutAddMenuEntry("画线", 1); glutAddMenuEntry("种子填充", 2); glutAttachMenu(GLUT_RIGHT_BUTTON); glutMainLoop(); }